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  <div class="section" id="allocating-objects-on-the-heap">
<span id="allocating-objects"></span><h1>Allocating Objects on the Heap<a class="headerlink" href="#allocating-objects-on-the-heap" title="Permalink to this headline">¶</a></h1>
<dl class="function">
<dt id="c._PyObject_New">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <tt class="descname">_PyObject_New</tt><big>(</big><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em><big>)</big><a class="headerlink" href="#c._PyObject_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em></dd></dl>

<dl class="function">
<dt id="c._PyObject_NewVar">
<a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a>* <tt class="descname">_PyObject_NewVar</tt><big>(</big><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em>, Py_ssize_t<em>&nbsp;size</em><big>)</big><a class="headerlink" href="#c._PyObject_NewVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em></dd></dl>

<dl class="function">
<dt id="c.PyObject_Init">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a>* <tt class="descname">PyObject_Init</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*op</em>, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em><big>)</big><a class="headerlink" href="#c.PyObject_Init" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>Initialize a newly-allocated object <em>op</em> with its type and initial
reference.  Returns the initialized object.  If <em>type</em> indicates that the
object participates in the cyclic garbage detector, it is added to the
detector&#8217;s set of observed objects. Other fields of the object are not
affected.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_InitVar">
<a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a>* <tt class="descname">PyObject_InitVar</tt><big>(</big><a class="reference internal" href="structures.html#c.PyVarObject" title="PyVarObject">PyVarObject</a><em>&nbsp;*op</em>, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em>, Py_ssize_t<em>&nbsp;size</em><big>)</big><a class="headerlink" href="#c.PyObject_InitVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: Borrowed reference.</em><p>This does everything <a class="reference internal" href="#c.PyObject_Init" title="PyObject_Init"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_Init()</span></tt></a> does, and also initializes the
length information for a variable-size object.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_New">
TYPE* <tt class="descname">PyObject_New</tt><big>(</big>TYPE, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em><big>)</big><a class="headerlink" href="#c.PyObject_New" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Allocate a new Python object using the C structure type <em>TYPE</em> and the
Python type object <em>type</em>.  Fields not defined by the Python object header
are not initialized; the object&#8217;s reference count will be one.  The size of
the memory allocation is determined from the <a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_basicsize" title="PyTypeObject.tp_basicsize"><tt class="xref c c-member docutils literal"><span class="pre">tp_basicsize</span></tt></a> field of
the type object.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_NewVar">
TYPE* <tt class="descname">PyObject_NewVar</tt><big>(</big>TYPE, <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject">PyTypeObject</a><em>&nbsp;*type</em>, Py_ssize_t<em>&nbsp;size</em><big>)</big><a class="headerlink" href="#c.PyObject_NewVar" title="Permalink to this definition">¶</a></dt>
<dd><em class="refcount">Return value: New reference.</em><p>Allocate a new Python object using the C structure type <em>TYPE</em> and the
Python type object <em>type</em>.  Fields not defined by the Python object header
are not initialized.  The allocated memory allows for the <em>TYPE</em> structure
plus <em>size</em> fields of the size given by the <a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_itemsize" title="PyTypeObject.tp_itemsize"><tt class="xref c c-member docutils literal"><span class="pre">tp_itemsize</span></tt></a> field of
<em>type</em>.  This is useful for implementing objects like tuples, which are
able to determine their size at construction time.  Embedding the array of
fields into the same allocation decreases the number of allocations,
improving the memory management efficiency.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_Del">
void <tt class="descname">PyObject_Del</tt><big>(</big><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*op</em><big>)</big><a class="headerlink" href="#c.PyObject_Del" title="Permalink to this definition">¶</a></dt>
<dd><p>Releases memory allocated to an object using <a class="reference internal" href="#c.PyObject_New" title="PyObject_New"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_New()</span></tt></a> or
<a class="reference internal" href="#c.PyObject_NewVar" title="PyObject_NewVar"><tt class="xref c c-func docutils literal"><span class="pre">PyObject_NewVar()</span></tt></a>.  This is normally called from the
<a class="reference internal" href="typeobj.html#c.PyTypeObject.tp_dealloc" title="PyTypeObject.tp_dealloc"><tt class="xref c c-member docutils literal"><span class="pre">tp_dealloc</span></tt></a> handler specified in the object&#8217;s type.  The fields of
the object should not be accessed after this call as the memory is no
longer a valid Python object.</p>
</dd></dl>

<dl class="var">
<dt id="c._Py_NoneStruct">
<a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a> <tt class="descname">_Py_NoneStruct</tt><a class="headerlink" href="#c._Py_NoneStruct" title="Permalink to this definition">¶</a></dt>
<dd><p>Object which is visible in Python as <tt class="docutils literal"><span class="pre">None</span></tt>.  This should only be accessed
using the <a class="reference internal" href="none.html#c.Py_None" title="Py_None"><tt class="xref c c-macro docutils literal"><span class="pre">Py_None</span></tt></a> macro, which evaluates to a pointer to this
object.</p>
</dd></dl>

<div class="admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt><a class="reference internal" href="module.html#c.PyModule_Create" title="PyModule_Create"><tt class="xref c c-func docutils literal"><span class="pre">PyModule_Create()</span></tt></a></dt>
<dd>To allocate and create extension modules.</dd>
</dl>
</div>
</div>


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